The present invention relates to a calculus crushing apparatus for crushing a calculus produced in the body cavity.
Calculi produced in the bile duct, bladder and other internal organs adversely influence the human body, and hypertrophied calculi are extremely painful.
Thereupon, calculus crushing apparatuses have conventionally been developed which are inserted into the body cavity through an endoscope. These apparatuses are used to crush or completely remove a calculus in the body cavity from the cavity. According to one such prior art crushing apparatus, a catch basket formed of resilient wires is fixed to the distal end of an operating wire, and the operating wire, along with the basket, is inserted into a flexible sheath having a rigid portion at its distal end. The basket is spread or folded by advancing or retreating the operating wire at the rear end of the sheath. After seizing the calculus by means of the basket projecting from the distal end of the sheath, the operating wire is pulled to draw the basket into the sheath. Thus, the basket is folded to break the calculus therein into small pieces.
In the crushing apparatus of this type, the flexible sheath is formed of a close coil or other suitable material which is strong enough to stand a force applied thereto during a calculus crushing operation. The close coil, however, is extremely stable and exhibits strong resistance to bending. Therefore, the sheath cannot easily be inserted into curved regions of a body cavity, e.g., into the bile duct via the duodenal papilla, and may possibly injure or puncture the body wall during the insertion.
Such a situation may be eliminated by using a sufficiently flexible material for the flexible sheath. In this case, however, the sheath would not be strong enough to resist the force exerted thereon during the crushing operation, and thus fail to reliably crush the calculus.